Field of the Invention
The present Invention relates to a toner for use in an image-forming method for developing electrophotographic end electrostatic images.
Description of the Related Art
In a common electrophotographic method, a latent image is formed on an image-bearing member (photoreceptor drum), toner is supplied to the latent image to obtain a visible image, and the toner image is transferred to paper or another transfer material and then fixed by heat or pressure on the transfer material to obtain a copied article. Printers using a high-speed one-component developing system have been used to satisfy demands for smaller alia, higher speeds and greater stability. Because the toner and the charging water contact each other less in a one component developing system than in a two-component developing system using a carrier, a relatively large stress must be applied to the toner to obtain the charge quantity, and consequently the load applied to the toner is known to be high.
For the toner used in a one-component developing system, a spherical toner with a sharp particle size distribution is desirable because it provides excellent transferability and fine line reproducibility among other features. However, in system in which the toner is cleaned from the photoreceptor drum with a cleaning blade, cleaning becomes more difficult the greater the circularity of the toner. One reason for this is thought to be that a high degree of circularity causes the toner to roll, making it more likely to slip through the contact nip between the cleaning blade and the photoreceptor.
One strategy chat has been adopted for preventing faulty cleaning with a conventional spherical toner is to increase the linear pressure applied to the edge of the blade in a blade-type cleaning system, thus preventing the spherical toner from slipping through. However, simply increasing the linear pressure nay lead to such problems as increased cracking of the blade edge, abnormal noise caused by blade chatter vibration, and increased wear to the photoreceptor due to contact with the blade. Thus, toner cleaning performance must be improved without relying solely on linear pressure in order to meet future needs for higher speeds and longer operating lives.
To this end, Japanese Patent Application Publication No. 2012-208492 proposes a toner with improved functionality obtained by fixing a resin particle with various additional functions to the surface of a toner base particle.
Japanese Patent Application Publication No. 2012-8555 proposes a toner wherein the attachment force of the toner has been reduced by keeping the embedding ratio of a resin particle within a specific range.